JP2013183457A - Management method, management apparatus, and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate optimal reception of multicast streams.SOLUTION: The method manages the transmission of data streams from a content server (4) to a plurality of receivers (8). The transmission of the data streams is possible over at least one broadcast network (20) made up of several transport streams and over a broadband network (24). The method comprises a step of reorganization of the data streams on the transport streams to ensure that more receivers receive the data streams over the broadcast network (20) after the reorganization.

Description

  The present invention relates generally to the technical field of broadcast multicast service communications over broadcast and broadband networks.

  In particular, the present invention relates to selecting an optimal network for delivering content traffic. The present invention is particularly applicable to devices that make such selections at a headend such as a multicast proxy.

  The present invention therefore relates to a method, apparatus and system for managing the transmission of data streams. The present invention also relates to a corresponding receiving apparatus and a computer program for executing the inventive method.

  Although the method described in this section may be feasible, it is not necessarily the method or the like that has been considered or implemented before the application of the present application. In other words, unless otherwise specified, the method described in this section is not necessarily the prior art for the present invention, and it is not recognized as the prior art by referring to this section.

  As the use of the Internet has become widespread, the Internet Protocol (IP) is now the basic communication protocol used to relay data packets over multiple networks.

  The most common form of IP communication is unicast communication. In the case of unicast communication, communication in which individual addresses of nodes are specified in transmitted packets is performed between nodes. This unicast communication is not suitable for distributing a large amount of content to many destinations.

  In order to respond to requests for transmitting Internet communication signals to many destinations, a multicast method referred to as IP multicast can be used. IP multicast is a one-to-many and many-to-many real-time communication method over IP infrastructure in the network. It can be tailored to an environment with a large number of receivers without requiring prior knowledge of who or how many receivers are present. Multicast can efficiently use network resources by requiring a source to send a data packet only once, even if it needs to be delivered to multiple receivers. A given node in the network, typically a network switch, switching center and router, duplicates the packet so that it reaches multiple receivers, so that the message is sent only once through each network link .

  The IP multicast uses an addressing method based on a group address. For example, in the case of IP-TV (Internet Protocol Television), the IP address specifies or designates a multicast group that is a TV channel / stream.

  IP multicast is also related to an IP signaling campaign protocol called Internet Group Management Protocol (IGMP), which is used by terminals and / or applications to notify connection and / or separation to a group such as a TV channel. used. The IGMP protocol allows IP networks with one or more routers to optimize the delivery of IP multicast traffic by forwarding IP multicast packets only to branches where at least one group member is advertised .

  Another way to allow content to be sent to multiple destinations is a specific digital television over cable (e.g. DVB-C), satellite (e.g. DVB-S) or terrestrial (e.g. DVB-T) link Broadcast. Broadcast differs from IP transmission in that communication is essentially unidirectional.

  Recently, broadcast networks have been developed to transmit IP streams including IP multicast streams.

  For example, according to Patent Document 1, the optimal network for delivering an IP multicast service between broadcast unidirectional links or broadband links such as DVB-T, DVB-C or DVB-H is selected at the headend. A method is disclosed. A device that makes this selection is referred to as a multicast proxy.

European Patent Application No. 1298836

  However, existing methods are not efficient enough to ensure that the largest number of users on the broadcast link receive the IP multicast stream and maximize the bandwidth savings.

  Furthermore, for transmission over a broadcast network, the data stream is packetized into transport streams known as TS or MPEG-TS (MPEG Transport Stream), each of which is distributed at various frequencies. On the receiver side, the broadcast adapter can tune to only one frequency, ie it can only receive one transport stream at a time. Thus, if two IP multicast streams are in two separate transport streams even though they are available on the same broadcast network, the receiver selects the best transport stream for the broadcast adapter to receive. There must be. Therefore, the IP multicast stream distributed by the other transport stream cannot be received by the broadcast adapter. This mechanism for IP multicast streams is not appropriate from the point of view that the broadcast adapter preferably receives both multicast streams.

  An object of the disclosed invention is to appropriately receive a multicast stream.

The management method according to the disclosed invention is:
A management method for managing transmission of a data stream from a content server to a plurality of receivers,
The transmission of the data stream can be performed via at least one broadcast network and a broadband network in which a plurality of transport streams are formed,
The management method includes a confirmation step of confirming the data stream of the transport stream and ensuring that more receivers receive the data stream via the broadcast network after confirmation. ,
In the checking step, the management method redesignates at least one data stream as a transport stream according to the number of receivers interested in receiving the data stream and / or the bandwidth of the data stream. is there.

1 conceptually shows an example of a communication system using the method according to the invention. The figure which shows the signal structure in a broadcast network. 1 is a flowchart showing a method according to a first embodiment of the present invention. 5 is a flowchart showing a method according to a second embodiment of the present invention. 6 is a flowchart showing a method according to a third embodiment of the present invention; Flowchart illustrating a method according to a fourth embodiment of the invention The figure which shows notionally a mode that it switches between two transport streams in a receiver. 1 is a schematic view of an apparatus according to the invention. 1 is a schematic diagram of a receiving device according to the present invention.

<Outline of the invention>
The present invention proposes a means to improve the situation.

(1) The method provided by the present invention is:
A management method for managing transmission of a data stream from a content server to a plurality of receivers, wherein the transmission of the data stream is performed through at least one broadcast network and a broadband network in which a plurality of transport transport streams are formed. The management method confirms the data stream of the transport stream, and after the confirmation, more receivers receive the data stream via the broadcast network. Has a confirmation step to guarantee

  The method according to the present invention allows a data stream to be dynamically assigned or assigned to a transport stream available in a broadcast network, thereby maximizing broadband bandwidth.

  Advantageously, in the checking step, at least one data stream is designated as a transport stream, depending on the number of receivers interested in receiving the data stream and / or the bandwidth of the data stream. You may fix it.

  The redesignated data stream may have been transmitted over a broadband network or multiple transport streams prior to confirmation.

(2) According to the first embodiment, in the case where the first data stream is distributed only via the broadband network, the management method includes:
Identifying a second data stream that is distributed in a second transport stream via the broadcast network;
Assigning the second data stream to the broadcast network;
For each transport stream of the broadcast network, calculating the number of receivers requesting the first data stream and having already received at least one other data stream in the transport stream;
Selecting a third transport stream as the transport stream associated with the maximum number of receivers;
Comparing the second transport stream and the third transport stream;
Assigning the first data stream to the second transport stream instead of the second data stream if the third transport stream is equal to the second transport stream;
If the third transport stream is equal to the second transport stream;
(a) selecting a data stream requested by fewer receivers delivered in the third transport stream;
(b) For the third data stream, after the confirmation, confirm a first condition that ensures that more receivers receive the data stream via the broadcast network;
(c) If the first condition is satisfied, the third data stream is assigned to the second transport stream instead of the second data stream, and the third data stream is substituted for the third data stream. Assigning one data stream to the third transport stream.

  This embodiment allows a first data stream received via a broadband network to be assigned or designated to a selected transport stream in the broadcast network. This means that the first data stream will be delivered in the selected transport stream. This assignment or designation may be determined, determined or determined by a reconfiguring device such as a multicast proxy. This occurs after receiving a request from a receiver to receive a multicast stream or to stop receiving another multicast stream that will replace it. In the case of this embodiment, it is possible to select an optimal transport stream for delivering a data stream while maximizing the number of receivers. Two methods are possible. They are simply replaced by the first data stream in the second transport stream, or re-configured with an intermediate or provisional assignment. Which method to choose depends on the number of receivers that prefer that method.

(3) According to the second embodiment, when the first data stream requested by the receiver is distributed via the broadcast network as a first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
Identifying a second data stream to be delivered in the second transport stream having sufficient bandwidth to deliver the first data stream;
With respect to the second data stream, after the confirmation, confirms a second condition that ensures that more receivers receive the data stream via the broadcast network;
If the second condition is satisfied, the second data stream is assigned to the first transport stream, and the first data stream is assigned to the second transport stream instead of the second data stream. Assign to.

(4) According to the third embodiment, in the case where the first data stream requested by the receiver is distributed via the broadcast network as the first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
A group of data streams having sufficient bandwidth to deliver the data stream already received in the second transport stream, different from the first data stream and in the first transformer Identify a group of data streams delivered in a port stream,
For the identified group of data streams, after the confirmation, confirm a third condition that ensures that more receivers receive the data stream via the broadcast network;
When the third condition is satisfied, the group of data streams is assigned to the second transport stream, and the already received data stream is substituted for the first transport stream instead of the group of data streams. Assign to.

  This is because all the data streams (i.e. already already) in the same transport stream as the first transport stream if the available bandwidth in the second transport stream already received is not sufficient. The receiver can receive the received data stream and the requested data stream).

(5) According to the fourth embodiment, in the case where the first data stream requested by the receiver is distributed via the broadcast network as the first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
Identifying a third transport stream that is different from the first transport stream and the second transport stream;
A set of data streams having sufficient bandwidth to deliver together the data stream already received in the second transport stream and the first data stream and delivered in the third transport stream; Identify the data stream,
For the identified group of data streams, after the confirmation, confirm a fourth condition that ensures that more receivers receive the data stream via the broadcast network;
If the fourth condition is satisfied, assign the group of data streams to the first and second transport streams, and replace the group of data streams with the already received data stream and the first A data stream is assigned to the third transport stream.

  This is because all data streams (i.e., the same transport stream, i.e., the first transport stream that is delivering the requested data stream even if it is already received) The receiver can receive the already received data stream and the requested data stream).

  The second, third and fourth embodiments have the advantage that the receiver can receive the requested data stream while continuing to receive the data stream already received on the broadband network.

  (6) Advantageously, the method is such that if the receiver is affected by the confirmation step of confirming the data stream, the data stream received by the receiver is a first transport stream in a first network. The method may further comprise the step of transmitting to the receiver a message indicating that it is to be transferred to the second transport stream.

  Thus, the receiver is notified of the change and may request that the same data be received on a second network, for example a broadband network, so that the reception of the data stream is not interrupted or reset. Even if an interruption occurs, it can be assured that the interruption is as short as possible. Thus, when the transport stream switches to another, the receiver can be unaffected by any stream discontinuity or be the shortest even if there is a stream discontinuity.

  (7) The data stream may form a broadcast and / or multicast stream.

  As already known, when distributed over a broadband network, the broadcast stream may be what is called an “IPTV service”, ie a multicast stream.

  In the preferred embodiment, the multicast stream is an IP multicast stream.

(8) An apparatus provided by the present invention is a management apparatus that manages transmission of a data stream from a content server to a plurality of receivers.
Each transmission of the data stream to each of the receivers can be performed via at least one broadcast network and a broadband network in which a plurality of transport streams are formed,
The management apparatus includes a reconfiguration unit that confirms the data stream of the transport stream and, after the confirmation, ensures that more receivers receive the data stream via the broadcast network. .

  This management apparatus is, for example, a multicast proxy.

  Advantageously, the resetting unit designates at least one data stream as a transport stream, depending on the number of receivers interested in receiving the data stream and / or the bandwidth of the data stream. Has a reassignment module.

(9) An apparatus further provided by the present invention is a receiving apparatus capable of receiving a data stream from a content server via at least one broadcast network and receiving a data stream from the content server via a broadband network,
A first module for receiving a message from a device indicating that a data stream received by the receiving device is moved from a first transport stream to a second transport stream in a first network;
And a second module for transmitting a request to receive the data stream via a second network.

  This receiving apparatus is, for example, a gateway.

  (10) According to one embodiment, the first network may be the broadcast network, and the second network may be the broadband network.

  (11) According to another embodiment, the first and second networks may be broadcast networks.

  If the second network is a broadcast network, the request is advantageously sent to the device according to the invention. If the second network is a broadband network, the request is advantageously transmitted over the broadband network in a conventional manner using the IGMP protocol.

  The method according to the invention may be realized by software in a programmable device. The present invention may be realized by hardware, software, or a combination thereof.

  Since the present invention can be implemented by software, the present invention may be incorporated as computer readable code that forms a programmable device on any suitable recording medium. The recording medium is a concept including a storage device such as a floppy disk, a CD-ROM, a hard disk drive, a magnetic tape device, or a solid state device.

  (12) Accordingly, the present invention also provides a computer program having instructions (computer readable instructions) for causing a computer to execute the method according to the present invention. Figures 3-6 show an example of a conceptual algorithm for such a computer program.

<Explanation of drawings>
The present invention will be described by way of non-limiting example with reference to the accompanying drawings, in which like reference numbers indicate like elements.

  FIG. 1 is a diagram conceptually illustrating an example of a communication system using the method according to the present invention.

  FIG. 2 is a diagram showing a signal configuration in the broadcast network.

  FIG. 3 is a flowchart showing a method according to the first embodiment of the present invention.

  FIG. 4 is a flowchart showing a method according to the second embodiment of the present invention.

  FIG. 5 is a flowchart showing a method according to the third embodiment of the present invention.

  FIG. 6 is a flowchart showing a method according to the fourth embodiment of the present invention.

  FIG. 7 is a diagram conceptually showing how the receiver switches between two transport streams.

  FIG. 8 is a schematic view of an apparatus according to the present invention.

  FIG. 9 is a schematic diagram of a receiving apparatus according to the present invention.

<Detailed Description of Preferred Embodiment>
Referring to FIG. 1, a schematic diagram of a communication system 2 that combines a plurality of communication links to transmit a data stream from a content server 4 to a home network 6 is shown.

  The home network 6 has a gateway 8 connected to several clients 9. The client 9 is typically a terminal such as a TV set, a set top box, or a portable device.

  The gateway 88 has broadcast adapters 10 and 12 and a broadband adapter 14.

  For example, the broadcast adapter 10 is a DVB-T broadcast adapter that can receive a broadcast transport stream from the DVB-T network 20, but the broadcast adapter 12 can receive a transport stream from the DVB-C network 22. It is an adapter. The broadcast networks 20 and 22 allow only one-way downlink communication as indicated by the arrow 23.

  The broadband adapter 14 can receive data transmitted via the broadband network 24. The broadband adapter is, for example, an ADSL receiver. The broadband network 24 allows two-way communication with the gateway 8 as indicated by the arrow 26.

  Networks 20, 22, and 24 belong to one or more operators.

  Therefore, in the system 2, the data transmitted from the content server 4 is transmitted to the home network 6 through the broadcast network 20 and 22 to which the broadcast adapters 10 and 12 are related and through the broadband network 24 to which the broadband adapter 14 is related. Received by the gateway 8. Router 32 can send data to each of these networks.

  The DVB-T network 20 includes a DVB-T router 34 and a DVB-T transport stream management unit 38.

  Similarly, the DVB-C network 22 includes a DVB-C router 38 and a DVB-C transport stream management unit 40.

  The broadband network has an edge router 42.

  The communication system 2 is also provided with a multicast proxy 44. The multicast proxy 44 is connected or linked to the routers 34, 38, 42 of the networks 20, 22, 24, respectively.

  The communication system 2 functions as follows.

  A data stream (forming an IP multicast stream and a broadcast stream) that can be used by the content server 4 is transmitted to the router 32, and the router 32 can route or distribute the data stream to the networks 20, 22, and 24.

  If the client 9 wishes to receive a particular broadcast or multicast service, the multicast proxy 44 selects the networks 20, 22, 24 that provide that service to the client 9. In accordance with the present invention, the selection is made to ensure that the majority of receivers receive the data stream via the broadcast networks 20, 22 to save bandwidth on the broadband network 24.

  After making this selection, the multicast proxy 44 notifies the gateway 8 which network distributes the requested content.

  When the selected network is the broadcast network 20 or 22, the configuration of the transport stream determined by the multicast proxy 44 is notified to the related transport stream management units 36 and 40, and the transport stream management is performed accordingly. Sends the requested data stream.

  As is known in the art, each of the broadcast networks 20, 22 is formed by a number of transport streams, each of which is distributed at a different frequency. A transport stream provides or delivers several services. A transport stream encapsulates a packetized data stream. For example, each piece of data such as an IP multicast stream or a broadcast stream in a transport stream is identified or specified by a 13-bit packet identifier called PID.

  For simplicity, only the broadcast DVB-T network 20 is considered in the following description.

  FIG. 2 shows an example of the initial configuration of the broadcast network 20. This is formed by three transport streams TS1, TS2, and TS3, and each transport stream distributes broadcast and IP multicast streams.

For the example shown:
The transport stream TS1 delivers IP multicast streams MS1, MS4 in addition to the broadcast streams BS11, BS12, BS13.

  The transport stream TS2 delivers IP multicast streams MS3, MS8, MS9, MS11 in addition to the broadcast streams BS21, BS22.

  The transport stream TS3 delivers IP multicast streams MS6 and MS7 in addition to the broadcast streams BS31, BS32 and BS33.

  Reference numeral 50 in FIG. 2 indicates a bandwidth that can be used in the transport streams TS1 and TS3.

  On the receiver side, the broadcast adapter 10 can tune to only one frequency, ie the broadcast adapter 10 can only receive one transport stream at a time. Thus, if the client 9 wants two IP multicast streams delivered via two separate transport streams (e.g., MS1 and MS3 delivered via transport streams TS1 and TS2), the gateway 8 Will receive one multicast stream (eg, MS1) via the broadcast network 20 and the other multicast stream (eg, MS3) via the broadband network. As a result, broadband bandwidth is depleted. In the present invention, the multicast proxy 44 uses the resetting unit (or setting unit) 60 shown in FIG. 8 to reset the setting, arrangement, or assignment of at least the multicast stream in the transport stream, and The largest number of receivers receive over the broadcast network so that broadband bandwidth can be saved. Therefore, in the case of the present invention, the gateway 8 can receive both the multicast streams MS1 and MS3 in the same transport stream.

  The following description focuses on the reconfiguration or rearrangement of the IP multicast stream in the transport stream of the broadcast network 20. However, similar processing may be applied to reconfiguration or rearrangement of the broadcast stream.

  The described embodiments of the invention make use of information about IP multicasts requested and / or received by the gateways from the gateways to the multicast proxy 44 about multicasts.

  The multicast proxy 44 maintains or maintains a first table, which includes, for example, a list of gateways requesting that stream for each IP multicast stream represented by an IP address, for example. It is expressed by the IP address. This table also contains additional information about each multicast stream, such as distribution networks such as broadcast or broadband, transport streams (for broadcast networks), PID (for broadcast networks), bandwidth, etc. Information is also included. Hereinafter, this table is referred to as an “IP multicast stream table”. Thanks to this table, the multicast proxy 44 allows the multicast stream to be routed through the broadcast network 20 or the broadcast band network 24 according to appropriate criteria such as the number of gateways requesting the stream, the requested bandwidth, etc. The multicast proxy 44 notifies at least each of the gateways involved in the change when the change occurs in the setting, arrangement, or assignment of the stream.

  Table 1 shows an example of an IP multicast stream table based on the broadcast network configuration shown in FIG.

好適な実施の形態の場合、マルチキャストプロキシ44は「ゲートウェイテーブル」と言及される第2のテーブルも保持又は維持している。このテーブルはIPマルチキャストストリームテーブルから得られ、ゲートウェイ各々により要求及び/又は受信されるIPマルチキャストストリームを直接的な形式で提供することを意図している。 <Table 1>

In the preferred embodiment, multicast proxy 44 also maintains or maintains a second table referred to as the “gateway table”. This table is derived from the IP multicast stream table and is intended to provide in direct form the IP multicast stream requested and / or received by each gateway.

  Table 2 shows a specific example of the gateway derived from Table 1.

好適な実施の形態の場合、双方のテーブルを保持し、その分メモリの容量を消費することになる。しかしながら、所与のゲートウェイにIPマルチキャストを直接的に提供できる点で有利である。 <Table 2>

In the preferred embodiment, both tables are held, and the memory capacity is consumed accordingly. However, it is advantageous in that it can provide IP multicast directly to a given gateway.

  In an alternative embodiment, only the IP multicast table is stored, and the multicast proxy 44 must systematically analyze the entire table to keep track of the IP multicast stream for a given gateway. This analysis consumes computational resources.

  In the following description, it is assumed that the multicast proxy 44 holds both tables.

  The main criteria for reconfiguring the various transport streams by changing the configuration, placement or assignment of the IP multicast stream is that more gateways are broadcast network 20 later than before reconfiguration. To ensure that an IP multicast stream is received via

  FIG. 3 illustrates such reconfiguration or reconfiguration when the multicast proxy 44 initially delivered an IP multicast stream over the broadband network 24 but decided to deliver over the broadcast network 20. The procedure is shown in a flowchart.

  If multicast proxy 44 decides to deliver IP multicast stream MISnew over broadcast network 20, this stream replaces another multicast stream MISold that was originally delivered in transport stream TSold, which is a broadband network. Will be delivered via 24. This is the case when there is enough unused bandwidth to perform such an operation.

  For example, if MISold is the least requested IP multicast stream delivered over broadcast network 20, while MISnew indicates that there are more gateways requesting it than MISold, the above decision will be multicast proxy. 44.

  The principle of the algorithm represented in Fig. 3 is whether or not the majority of gateways want to simply replace MISold with MISnew in TSold, or its optimization can be obtained by a number of intermediate reconfigurations. It is to determine whether or not.

  In an initial step 100, the multicast proxy 44 decides to distribute MISnew via the broadcast network 20 and distribute MISold via the broadband network 24. Thus, the multicast proxy 44 updates the two tables in step 102 by deleting all references that point to the stream MISold to be replaced that will be delivered over the broadband network.

  Next, in step 104, the multicast proxy 44 looks for all receivers (ie, gateways) that are interested in MISnew and are receiving at least one other IP multicast stream via the broadcast network 20. Considering only gateways that satisfy this condition, the multicast proxy 44 counts, for each transport stream of the broadcast network 20, the number of gateways that receive the IP multicast stream distributed in the transport stream. Next, the transport streams are arranged in a list referred to as a “TS list”, from the one that shows the most gateways to the one that shows the minimum number of gateways.

  In step 106, the multicast proxy 44 determines whether or not the “TS list” is empty (whether or not there is a free space).

  If the “TS list” is empty, in step 108 the new MISnew is simply replaced with MISold.

  To do this in a manner that is gentle for the gateways affected by this decision (in a seamless manner), the multicast proxy 44 notifies those gateways of the change before both MISnew and MISold are moved. For example, the multicast proxy 44 sends a first message to the gateway that will receive MISnew via the broadcast network 20, and requests the delivery of MISold via the broadband network 24, for example by an IGMP joint request. Send a second message to the gateway.

  Next, before returning to the initial state 100, the multicast proxy 44 updates the above two tables by adding a reference that points to the new multicast stream MISnew.

  Preferably, the multicast proxy 44 notifies the gateway of the change and then waits until the multicast stream is reconfigured so that the gateway can prepare to receive the multicast stream on the network designated by each gateway. To.

  If the “TS list” is not empty, the multicast proxy 44 obtains from the TS list transport streams (referred to as TSnew) for the largest number of gateways at step 110.

  In step 112, the multicast proxy 44 compares TSnew and TSold.

  If TSnew is a transport stream that has delivered MISold (ie, TSold), multicast proxy 44 proceeds to step 108.

  As a specific example, the multicast proxy 44 determines to replace the IP multicast stream MS4 related to the gateways G1 and G3 with the IP multicast stream MS2 related to the gateways G4 and G4. The gateway G4 also receives the IP multicast stream MS1 distributed by the transport stream TS1, and the gateway G5 also receives the IP multicast stream MS1 distributed by the broadband network 24. Accordingly, the number of gateways interested in the IP multicast stream MS2 and receiving at least one other IP multicast stream is expressed as in Table 3 below for each TS.

そして、最多クライアント数を伴うトランスポートストリームはTS1であり、IPマルチキャストMS4はTS1を介して配信されている。そこで、IPマルチキャストストリームMS2が、トランスポートストリームTS1において、IPマルチキャストストリームMS4に置き換わる。 <Table 3>

The transport stream with the largest number of clients is TS1, and the IP multicast MS4 is distributed via TS1. Therefore, the IP multicast stream MS2 is replaced with the IP multicast stream MS4 in the transport stream TS1.

  If TSnew is different from TSold, the multicast proxy 44 checks whether there is an IP multicast stream that can be transferred to TSold included in TSnew to release or reserve bandwidth for MISnew in TSnew. To do.

  For this reason, the multicast proxy 44 considers all multicast streams belonging to TSnew in the list referred to as “MIS candidate list” in step 114. The list is from the IP multicast stream with the smallest number of gateways of interest to the largest.

  In step 116, the multicast proxy 44 determines whether or not the “MIS candidate list” is empty.

  If the “MIS Candidate List” is not empty, then the multicast proxy 44 lists the IP multicast stream (referred to as “MISScandidate”) that has the lowest number of gateways of interest to the list at step 118. Get from.

  The condition for achieving the reconstruction of the multicast stream is to ensure that more clients will receive the multicast stream over the broadcast network after the reconstruction before.

This condition is expressed by the following formula C1:
(NnewTSnew * BWnew + NcanTSold * BWcan)> (NnewTSold * BWnew + NcanTSnew * BWcan)
In this case,
-NnewTSnew is the number of gateways interested in MISnew receiving at least one other multicast stream via TSnew;
-NcanTSold is the number of gateways interested in the MIS candidate receiving at least one other multicast stream via TSold;
-NnewTSold is the number of gateways interested in MISnew receiving at least one other multicast stream via TSold;
-NcanTSnew is the number of gateways interested in MIS candidates receiving at least one other multicast stream via TSnew;
-BWnew is the bandwidth occupied by MISnew,
-BWcan is the bandwidth occupied by MIS candidates.

  In step 120, the multicast proxy 44 determines whether or not the above formula C1 is violated together with the candidate multicast stream MIS candidate (whether the formula C1 is satisfied or satisfied).

  If the formula C1 is violated, the multicast proxy 44 deletes the MIS candidate from the “MIS candidate list” in step 122 and returns to step 116.

  If the expression C1 is not violated, the multicast proxy 44 replaces MISold with the MIS candidate in TSold and replaces the MIS candidate with MISnew in TSnew in step 124. In order to make a gentle change for the gateway affected by this determination or decision, the multicast proxy 44 notifies the gateway of the change before moving the multicast stream. Then, the multicast proxy 44 sets MISnew in TSnew and sets MIS candidates in TSold using the reconfiguration module (or setting module) 62 shown in FIG. Update one table. Then, the multicast proxy 44 returns to the initial state 100.

  Preferably, the multicast proxy 44 notifies the gateway of the change and then waits until the stream is re-designated so that the gateway can prepare to start receiving the multicast stream with its new transport stream. To.

  If the “MIS candidate list” is empty, the multicast proxy 44 acquires the transport stream TSnew from the TS list in step 126 and returns to step 106.

  FIG. 4 shows a method according to the second embodiment of the present invention for resetting a transport stream when a request is received from the gateway 8 to receive an available IP multicast stream via the broadcast network 20. Shown in flow chart.

  In step 200, the multicast proxy 44 receives a request from the gateway 8, and the request indicates that the gateway wants to receive the IP multicast stream MISreq in the transport stream TSreq available via the broadcast network 20. Show.

  In step 202, the multicast proxy 44 checks or determines whether the gateway 8 already exists in the gateway table.

  If not, the multicast proxy 44 notifies the gateway 8 in step 204, for example by sending a message, and adds a reference pointing to the new gateway 8 and a reference indicating the requested multicast stream MISreq. Update the two tables. This situation indicates that the gateway's broadcast adapter 10 is not being used to receive another IP multicast stream being delivered in another transport stream. Thereafter, the multicast proxy returns to the initial state 200. A specific example of this situation is when the gateway G10 requests the IP multicast stream MS1.

  If the gateway 8 has already been referenced in the gateway table, i.e. it has received at least one IP multicast stream distributed by broadcast, the multicast proxy checks several things. In step 206, the multicast proxy 44 determines whether the broadcast network of the requested IP multicast stream is the same as the broadcast network 20 that has already received the multicast stream.

  If not, the requested multicast stream is the only one received on the broadcast network. Therefore, the broadcast adapter 10 is not used to receive another IP multicast stream that is distributed in another transport stream. In step 208, the multicast proxy 44 notifies the gateway 8 by sending a message, for example, and updates the two tables by adding a reference pointing to that gateway. Thereafter, the multicast proxy 44 returns to the initial state 200. A specific example of this situation is when the gateway G5 is requesting the IP multicast stream MS1.

  If one or more IP multicast streams have already been received by the gateway 8 in this broadcast network 20, the multicast proxy 44 determines in step 210 that the requested IP multicast stream and the IP multicast stream that has already been received. Are distributed in the same transport stream.

  In the following description, a list of IP multicast streams already received by the gateway 8 is referred to as a “received MIS list”, and when a multicast stream (already received multicast: arm) that has already been received is broadcast. This transport stream is referred to as “TSarm”.

  If the multicast stream that has already been received and the requested multicast stream are delivered in the same transport stream, that is, TSreq = TSarm, the gateway 8 has already received in addition to the requested IP multicast stream. Can also receive multicast streams that are subject to In step 212, the multicast proxy 44 notifies the gateway 8, for example, by sending a message, and updates the two tables by adding a reference indicating the gateway 8 and a reference indicating the requested multicast stream MISreq. . Thereafter, the multicast proxy 44 returns to the initial state 200. A specific example of this situation is when the gateway G2 requests the IP multicast stream MS9.

  If they have been delivered in separate transport streams, the multicast proxy 44 determines whether it is possible to move the requested multicast stream MISreq from the transport stream TSreq to the transport stream TSarm. For this reason, the multicast proxy 44 searches for an IP multicast stream to be transferred from TSarm to TSreq among IP multicast streams different from the multicast stream to be received.

  In step 214, the multicast proxy 44 makes a “candidate” along with all IP multicast streams (except those already received) included in the TSarm that can release enough bandwidth to deliver the MISreq. A list referred to as an “MIS list” is generated.

  In step 216, the multicast proxy 44 determines whether the list of candidate MISs is empty.

  In the case of the second embodiment, the list of candidate MISs is not empty. In step 218, the multicast proxy 44 obtains one IP multicast stream called a MIS candidate from the list of candidate MISs. The condition for resetting the IP multicast stream is to guarantee that more gateways will receive the IP multicast stream via the broadcast network 20 after the resetting.

The condition is expressed by the following formula C2:
(NreqTSarm * BWreq + NcanTSreq * BWcan)> (NreqTSreq * BWreq + NcanTSarm * BWcan)
In this case,
-NreqTSarm is the number of gateways interested in MISreq receiving at least one other multicast stream via TSarm;
-NcanTSreq is the number of gateways interested in MIS candidates receiving at least one other multicast stream via TSreq;
-NreqTSreq is the number of gateways interested in MISreq receiving at least one other multicast stream via TSreq;
NcanTSarm is the number of gateways interested in MIS candidates receiving at least one other multicast stream via TSarm;
-BWreq is the bandwidth occupied by MISreq,
-BWcan is the bandwidth occupied by MIS candidates.

  In step 220, the multicast proxy 44 determines whether or not the above formula C1 is violated (whether or not the formula C1 is satisfied or satisfied).

  If the expression C2 is violated, the multicast proxy 44 deletes this MIS candidate from the list of candidate MISs, and returns to Step 216.

  If the expression C2 is not violated, the multicast proxy 44 designates MISreq as TSarm and MIS candidate as TSreq in step 224. In order to make changes gently for gateways affected by this decision or decision, the multicast proxy 44 notifies those gateways of the changes. Then, the multicast proxy 44 sets MISreq in TSarm and sets MIS candidates in TSreq, and updates the two tables for the MISreq and the reference indicating the MIS candidates. Then, the multicast proxy 44 returns to the initial state 200.

  Preferably, the multicast proxy 44 notifies the gateway of the change and then waits until the stream is re-designated so that the gateway can prepare to start receiving the multicast stream with its new transport stream. To.

  FIG. 5 shows that when a request is received from the gateway 8 to receive an IP multicast stream available via the broadcast network 20, it exists in the transport stream already received by the gateway and has already been received. Unlike the multicast stream, the transport stream is reset when there is no IP multicast stream that can release enough bandwidth to deliver the requested IP multicast stream. The method according to this embodiment is shown in a flowchart.

  Steps 200 to 216 are the same as those in the second embodiment (FIG. 4). Therefore, those descriptions will not be repeated.

  In the third embodiment, the list of candidate MISs is empty, and the multicast proxy 44 can change the list of transport streams already received from the transport stream TSarm already received to the requested transport stream TSreq. It is determined whether or not. For this reason, a list of IP multicast streams that are different from MISreq and that can release a sufficient bandwidth to distribute a list of already received IP multicast streams that are changed from TSreq to TSarm is searched for.

  In step 230, the multicast proxy 44, together with all IP multicast streams in TSreq, which is different from MISreq and can release enough bandwidth to deliver the list of MISs to be received, together with the “list of candidate MIS TSreqs” Produces the list mentioned.

In step 232, the multicast proxy 44 determines whether there is a combination of candidate IP multicast streams (ie, one or more multicast streams in the list) that can release sufficient bandwidth and satisfy the following formula C3:
((Σ _{k = 0} ^N NarmTSreq _k * BWarm _k ) + (Σ _{k = 0} ^M NcanTSarm _k * BWcan _k ))
>
((Σ _{k = 0} ^N NarmTSarm _k * BWarm _k ) + (Σ _{k = 0} ^M NcanTSreq _k * BWcan _k ))
In this case,
-N is the number of IP multicast streams already received in TSarm,
-M is the number of IP multicast streams present in TSreq that are not MISreq and can release enough bandwidth to deliver a list of already received IP multicast streams;
NarmTSreq _k is the number of gateways that are receiving at least one other IP multicast stream via TSreq and are interested in the kth element in the list of already received IP multicast streams;
NcanTSarm _k is the number of gateways that are receiving at least one other IP multicast stream via TSarm and interested in the kth element in the candidate IP multicast stream combination;
NarmTSarm _k is the number of gateways that are receiving at least one other IP multicast stream via TSarm and are interested in the kth element in the list of already received IP multicast streams;
NcanTSreq _k is the number of gateways that are receiving at least one other IP multicast stream via TSreq and are interested in the kth element in the candidate IP multicast stream combination;
-BWarm _k is the bandwidth of the kth element in the list of already received IP multicast streams,
-BWcan _k is the bandwidth of the kth element in the candidate IP multicast stream combination.

  The above formula is examined for all combinations of IP multicast streams that can release sufficient bandwidth. The multicast proxy 44 determines whether at least one combination satisfies Formula C3.

For the third embodiment, the multicast proxy 44 considers the combination TSarm that yields the maximum value for the following formula at step 234:
((Σ _{k = 0} ^N NarmTSreq _k * BWarm _k ) + (Σ _{k = 0} ^M NcanTSarm _k * BWcan _k ))
−
((Σ _{k = 0} ^N NarmTSarm _k * BWarm _k ) + (Σ _{k = 0} ^M NcanTSreq _k * BWcan _k ))
Then, the multicast proxy 44 prevents all gateways from being affected by this determination, designates the already received IP multicast stream as TSreq and designates all MIS candidates by combination as TSarm, and all these IP multicasts. Update the two tables by adding a reference to the stream.

  FIG. 6 shows that when a request is received from the gateway 8 to receive an IP multicast stream available via the broadcast network 20, it exists in the transport stream already received by the gateway and has already been received. Unlike the multicast stream, the fourth aspect of the present invention reconfigures the transport stream when there is no multicast stream that can release enough bandwidth to deliver the requested IP multicast stream. The method by embodiment is shown with a flowchart. Furthermore, in the present embodiment, there is no combination of IP multicast streams that satisfy the condition C3 among the requested transport streams.

  Steps 200 to 232 are the same as those in the third embodiment (FIG. 5). Therefore, those descriptions will not be repeated.

  In the fourth embodiment, if the reconfiguration can ensure that more gateways will receive the IP multicast stream via the broadcast network 20, the multicast proxy 44 will request the requested IP multicast stream MISreq. In addition, it is determined whether or not there is a transport stream that can release a bandwidth sufficient to become a host of a list of IP multicast streams to be received and is different from TSreq and TSarm. Therefore, a transport stream having a group of IP multicast streams that can release sufficient bandwidth to distribute the requested IP multicast stream MISreq and the list of IP multicast streams already received is searched.

  In step 240, the multicast proxy 44 generates a list that includes all transport streams except TSreq and TSarm.

  In step 242, multicast proxy 44 determines whether the list is empty.

  If the list is empty, the multicast proxy returns to the initial state 200 without changing any mechanism of the transport stream.

  If the list is not empty, the multicast proxy 44 obtains one transport stream referred to as TScan from the list in step 244, and in step 246, sufficient bandwidth of all IP multicast streams in TScan. The presence / absence (that is, one or more) of candidate IP multicast streams that can release the width and satisfy the following formula C4 is determined.

((Σ _{k = 0} ^N NarmTScan _k * BWarm _k ) + (NreqTScan * BWreq) + (Σ _{k = 0} ^M NcanTSarm _k * BWcan _k )
+ (Σ _{k = 0} ^P NcanTSreq _k * BWcan _k ))
>
((Σ _{k = 0} ^N NarmTScan _k * BWarm _k ) + (NreqTSreq * BWreq) + (Σ _{k = 0} ^{M + P} NcanTScan _k * BWcan _k ))
In this case,
-N is the number of IP multicast streams already received in TSarm,
-M is the number of IP multicast streams present in TSreq that can release enough bandwidth to deliver a list of already received IP multicast streams;
-P is the number of IP multicast streams present in TSreq that can release enough bandwidth to deliver MISreq;
NarmTScan _k is the number of gateways that are receiving at least one other IP multicast stream via TScan and interested in the kth element in the list of IP multicast streams already received;
-NcanTSarm _k is the number of clients that are receiving at least one other IP multicast stream via TSarm and interested in the kth element in the candidate IP multicast stream combination;
-NreqTSarm _k is the number of clients interested in MISreq receiving at least one other IP multicast stream via TScan;
NarmTSarm _k is the number of clients that are receiving at least one other IP multicast stream via TSarm and are interested in the kth element in the list of already received IP multicast streams;
-NcanTScan _k is the number of clients that are receiving at least one other IP multicast stream via TScan and interested in the kth element in the combination of candidate IP multicast streams;
NreqTSreq _k is the number of clients interested in MISreq receiving at least one other IP multicast stream via TSreq;
-BWarm _k is the bandwidth of the kth element in the list of already received IP multicast streams,
BWcan _k is the bandwidth of the kth element in the candidate IP multicast stream combination,
-BWreq is the bandwidth of MISreq.

  The multicast proxy 44 examines the above formula for all combinations of IP multicast streams that can release sufficient bandwidth, and determines in step 246 whether at least one combination satisfies the above formula C4.

In that case, the multicast proxy 44 decides in step 248 to change to the combination of TSarm and TSreq that yields the highest value in the following equation:
((Σ _{k = 0} ^N NarmTScan _k * BWarm _k ) + (NreqTScan * BWreq) + (Σ _{k = 0} ^M NcanTSarm _k * BWcan _k )
+ (Σ _{k = 0} ^P NcanTSreq _k * BWcan _k ))
−
((Σ _{k = 0} ^N NarmTSarm _k * BWarm _k ) + (NreqTSreq * BWreq) + (Σ _{k = 0} ^{M + P} NcanTScan _k * BWcan _k ))
The multicast proxy 44 prevents all gateways from being affected by this determination, designates MISreq and all already received IP multicast streams as TScan, and designates MIS candidates as TSreq and TSarm. Next, the two tables are updated by managing references pointing to all these IP multicast streams. Then, the multicast proxy 44 returns to the initial state 200.

  If there is no combination that satisfies the condition C4, the multicast proxy 44 deletes the transport stream from the list of transport streams in Step 250 and proceeds to Step 242.

  FIG. 7 shows a procedure executed by the gateway 8 together with a time axis when resetting an IP multicast stream in the transport stream.

  The gateway 8 can receive only one transport stream at a time. Next, if the multicast proxy 44 reconfigures the IP multicast stream from the transport stream TS1 to another transport stream TS2 in the same broadcast network 20, the gateway 8 will be affected by the stream interruption during the switching, i.e. Not all IP multicast packets can be received. In order to avoid this problem, the gateway 8 uses the temporary stream in another network, for example the broadcast network 22 or the broadband network 24, so that the IP multicast stream can be received continuously.

  The provisional or temporary stream delivered via broadband is preferably slightly ahead of the same multicast stream delivered by transport stream TS1. Otherwise, discontinuity or discontinuity will occur.

  In step 300, the first module 70 of the gateway 8 shown in FIG. 9 receives a message indicating that the IP multicast stream is moved from TS1 to TS2. Next, the second module 80 of the gateway 8 shown in FIG. 9 requests in step 302 that the IP multicast stream is received on the broadband network 24 and continues to be received on the broadcast interface 10. When the gateway 8 starts to receive an IP multicast stream from the broadband network 24, the networks 20, 24 are not synchronized with each other, so the same IP multicast packet is received redundantly with some delay. Receiving the same packet twice is not a problem for the gateway. This is because it is sufficient to discard one.

  After sufficient time to ensure that all clients receive duplicate IP multicast streams, the multicast proxy 44 determines in step 304 that the IP multicast stream is no longer available in the old transport stream TS1, but is new. The transport stream TS2 is switched so that it can be used. The gateway 8 requires a delay time 306 for switching. During this delay time 306, the gateway 8 receives an IP multicast stream only from the broadband network 24.

  After the delay time 306 corresponding to the switching period, the gateway 8 receives the IP multicast stream also by the new transport stream TS2. This means that the multicast packet of the IP multicast stream is received redundantly. In step 308, the gateway 8 stops receiving the IP multicast stream via the broadband network 24 and only receives it via TS2.

  Thus far, what has been described and illustrated as preferred embodiments of the invention have been described and illustrated, but various other embodiments are possible without departing from the true scope of the invention. One skilled in the art will understand that some may be substituted for equivalents. Furthermore, many variations are possible by adapting the teachings of the present invention to a specific situation without departing from the essence of the inventive concept described herein. Furthermore, embodiments according to the invention may not include all of the features described above. That is, the invention is not limited to the specific embodiments described, but all embodiments according to the invention are intended to fall within the scope of the appended claims.

  Expressions such as “form”, “include”, “include”, “include”, “is” and “have” are interpreted in a non-limiting manner when interpreting this description and the appended claims. It should be taken, i.e. it is interpreted that there is room for other means and procedures not explicitly specified. Unless specifically limited, the means and procedures are not limited to be singular or plural.

  Various parameters described in this description may be changed and various forms described and / or claimed may be combined without departing from the scope of the present invention. This will be readily appreciated by those skilled in the art.

  In other words, the above description focused on reconfiguring an IP multicast stream in one broadcast network (DVB-T network), but the present invention is also applicable to reconfiguring an IP multicast stream in a plurality of broadcast networks. It is. That is, an IP multicast stream may be moved from one broadcast network to another if the condition is met for the majority of gateways.

  Further, the reconfiguration described above is based on information provided by the gateway and related to the IP stream received and / or transmitted by the gateway. That is, the multicast proxy does not know what broadcast stream each of the gateways is receiving. With this additional information, the multicast proxy can improve the ability to make reconfiguration decisions. This applies to both broadcast and IP multicast streams as well as IP multicast streams. If the gateway's broadcast adapter stops receiving the broadcast stream, tunes to the new transport stream, and starts receiving the broadcast stream again, moving the broadcast stream from one transport stream to another gently or seamlessly Achieved. This indicates that all parameters (such as PID) related to the transport stream are provided in the broadcast adapter.

2 Communication system
4 Content server
6 Home network
8 Gateway
9 clients
10, 12 Broadcast adapter
14 Broadband adapter
20, 22 Broadcast network
23, 26 Communication direction
24 Broadband network
34, 38 routers
36, 40 Transport Stream Management Department
42 Edge router
44 Multicast proxy

Claims (12)

A management method for managing transmission of a data stream from a content server to a plurality of receivers,
The transmission of the data stream can be performed via at least one broadcast network and a broadband network in which a plurality of transport streams are formed,
The management method includes a confirmation step of confirming the data stream of the transport stream and ensuring that more receivers receive the data stream via the broadcast network after confirmation. ,
A management method, wherein in the checking step, at least one data stream is redesignated as a transport stream according to the number of receivers interested in receiving the data stream and / or the bandwidth of the data stream. In the case where the first data stream is distributed only via the broadband network, the management method includes:
Identifying a second data stream that is distributed in a second transport stream via the broadcast network;
Assigning the second data stream to the broadcast network;
For each transport stream of the broadcast network, calculating the number of receivers requesting the first data stream and having already received at least one other data stream in the transport stream;
Selecting a third transport stream as the transport stream associated with the maximum number of receivers;
Comparing the second transport stream and the third transport stream;
Assigning the first data stream to the second transport stream instead of the second data stream if the third transport stream is equal to the second transport stream;
If the third transport stream is equal to the second transport stream;
(1) Select a data stream requested by fewer receivers delivered in the third transport stream;
(2) For the third data stream, after the confirmation, confirm a first condition that ensures that more receivers receive the data stream via the broadcast network;
(3) When the first condition is satisfied, the third data stream is assigned to the second transport stream instead of the second data stream, and the third data stream is replaced with the second data stream. 2. The management method according to claim 1, further comprising: assigning one data stream to the third transport stream. In the case where the first data stream requested by the receiver is delivered via the broadcast network in the first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
Identifying a second data stream to be delivered in the second transport stream having sufficient bandwidth to deliver the first data stream;
With respect to the second data stream, after the confirmation, confirms a second condition that ensures that more receivers receive the data stream via the broadcast network;
If the second condition is satisfied, the second data stream is assigned to the first transport stream, and the first data stream is assigned to the second transport stream instead of the second data stream. The management method according to claim 1, wherein the management method is assigned to. In the case where the first data stream requested by the receiver is delivered via the broadcast network in the first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
A group of data streams having sufficient bandwidth to deliver the data stream already received in the second transport stream, different from the first data stream and in the first transformer Identify a group of data streams delivered in a port stream,
For the identified group of data streams, after the confirmation, confirm a third condition that ensures that more receivers receive the data stream via the broadcast network;
When the third condition is satisfied, the group of data streams is assigned to the second transport stream, and the already received data stream is substituted for the first transport stream instead of the group of data streams. The management method according to claim 1, wherein the management method is assigned to. In the case where the first data stream requested by the receiver is delivered via the broadcast network in the first transport stream,
Identify a second transport stream that has already been received at the request of the receiver;
Identifying a third transport stream that is different from the first transport stream and the second transport stream;
A set of data streams having sufficient bandwidth to deliver together the data stream already received in the second transport stream and the first data stream and delivered in the third transport stream; Identify the data stream,
For the identified group of data streams, after the confirmation, confirm a fourth condition that ensures that more receivers receive the data stream via the broadcast network;
If the fourth condition is satisfied, assign the group of data streams to the first and second transport streams, and replace the group of data streams with the already received data stream and the first The management method according to claim 1, wherein a data stream is allocated to the third transport stream.   If the receiver is affected by the confirmation step of confirming the data stream, the data stream received by the receiver is moved from the first transport stream to the second transport stream in the first network. The management method according to claim 1, further comprising a step of transmitting a message to the receiver.   The management method according to claim 1, wherein the data stream forms a broadcast and / or multicast stream. A management device that manages transmission of data streams from a content server to a plurality of receivers,
Each transmission of the data stream to each of the receivers can be performed via at least one broadcast network and a broadband network in which a plurality of transport streams are formed,
The management apparatus has a resetting unit that confirms the data stream of the transport stream, and after the confirmation, ensures that more receivers receive the data stream via the broadcast network. And
The resetting unit comprises an allocation module for redesignating at least one data stream as a transport stream according to the number of receivers interested in receiving the data stream and / or the bandwidth of the data stream. Having a management device. A receiving device capable of receiving a data stream from a content server via at least one broadcast network and receiving a data stream from the content server via a broadband network,
A first module for receiving a message from a device indicating that a data stream received by the receiving device is moved from a first transport stream to a second transport stream in a first network;
And a second module for transmitting a request to receive the data stream via a second network.   The receiving apparatus according to claim 9, wherein the first network is the broadcast network, and the second network is the broadband network.   The receiving device according to claim 9, wherein the first and second networks are broadcast networks.   A computer program having instructions for causing a computer to execute the management method according to claim 1.

Images